INVESTMENT SECURITIES AVAILABLE FOR SALE - Continuous unrealized loss position (Details)	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2017 USD ($) item	Jun. 30, 2016 USD ($)	Jun. 30, 2017 USD ($) item	Jun. 30, 2016 USD ($)	Dec. 31, 2016 USD ($) item
Securities available for sale:
Less than 12 Months, Fair value	$ 93,613,000		$ 93,613,000		$ 169,216,000
Less than 12 Months, Unrealized loss			690,000		1,925,000
12 Months or more, Fair value	24,445,000		24,445,000		8,714,000
12 Months or more, Unrealized loss			180,000		109,000
Total, Fair value	$ 118,058,000		118,058,000		177,930,000
Total, Unrealized loss			$ 870,000		$ 2,034,000
Unrealized loss
Number of securities, unrealized losses | item	66		66		107
Aggregate depreciation	0.73%		0.73%		1.13%
Other than temporary impairment:
Other than temporary impairment, recognized as losses	$ 0	$ 0	$ 0	$ 824,000
U.S. Treasury securities
Securities available for sale:
Less than 12 Months, Fair value	7,957,000		7,957,000		$ 75,901,000
Less than 12 Months, Unrealized loss			36,000		72,000
12 Months or more, Fair value	17,979,000		17,979,000
12 Months or more, Unrealized loss			21,000
Total, Fair value	25,936,000		25,936,000		75,901,000
Total, Unrealized loss			57,000		72,000
Government sponsored entity debt securities
Securities available for sale:
Less than 12 Months, Fair value	13,419,000		13,419,000		4,107,000
Less than 12 Months, Unrealized loss			14,000		22,000
Total, Fair value	13,419,000		13,419,000		4,107,000
Total, Unrealized loss			14,000		22,000
Agency mortgage-backed securities
Securities available for sale:
Less than 12 Months, Fair value	59,248,000		59,248,000		57,882,000
Less than 12 Months, Unrealized loss			549,000		930,000
12 Months or more, Fair value	1,093,000		1,093,000		402,000
12 Months or more, Unrealized loss			41,000		2,000
Total, Fair value	60,341,000		60,341,000		58,284,000
Total, Unrealized loss			590,000		932,000
State and municipal securities
Securities available for sale:
Less than 12 Months, Fair value	7,877,000		7,877,000		20,215,000
Less than 12 Months, Unrealized loss			37,000		567,000
12 Months or more, Fair value	527,000		527,000
12 Months or more, Unrealized loss			3,000
Total, Fair value	8,404,000		8,404,000		20,215,000
Total, Unrealized loss			40,000		567,000
Corporate securities
Securities available for sale:
Less than 12 Months, Fair value	2,523,000		2,523,000		11,111,000
Less than 12 Months, Unrealized loss			44,000		334,000
12 Months or more, Fair value	4,846,000		4,846,000		8,312,000
12 Months or more, Unrealized loss			115,000		107,000
Total, Fair value	7,369,000		7,369,000		19,423,000
Total, Unrealized loss			159,000		$ 441,000
Equity securities
Securities available for sale:
Less than 12 Months, Fair value	2,589,000		2,589,000
Less than 12 Months, Unrealized loss			10,000
Total, Fair value	$ 2,589,000		2,589,000
Total, Unrealized loss			$ 10,000